1. Technical Field
The present invention relates to a fault diagnosis apparatus for a brake of a train, an automatic train operation system operated due to degradation of braking performance using the same, and a fault diagnosis method for the brake of the train, and more particularly, to a fault diagnosis apparatus for a brake of a train, an automatic train operation system using the same and a fault diagnosis method which are directed to diagnosing performance degradation or a fault in the brake of the train and report the diagnosis result to a control system, and safely moving the train to a stopping point through a powering operation or coasting operation such that emergency braking is not applied by an automatic train protection (ATP) system.
2. Description of the Related Art
Typically, a train refers to a vehicle which travels along a rail or a corresponding track, namely a railroad using wheels and is driven using motive power other than manpower or output. The train is provided with an engine for movement and a brake for controlling the speed of the moving train or stopping the moving train. If performance of the brake of the train is low, the train may not be stopped at an intended place and the train may not be safe from accidental dangers. To address such issues, various kinds of brakes including an adhesive brake, a non-adhesive brake, a tread brake, a disc brake, a generative brake, a regenerative brake, an eddy current disc brake, an engine brake, and a converter brake have been developed. However, even a train equipped with a brake exhibiting the best performance may have an accident if a fault occurs in the brake. Accordingly, not only research on improvement of brake performance but also research on fault diagnosis technology has been steadily conducted.
FIG. 1 is a conceptual diagram illustrating a conventional fault diagnosis apparatus for a train brake.
As shown in FIG. 1, the conventional fault diagnosis system for a train brake includes: a powering signal detector 8 for detecting voltages of contact signals of various relays installed in an electric train; a first DC/DC converter 11 for converting DC voltages output from the powering signal detector 8 and voltages of a VCB state and signals for dead section entrance/pass into DC voltages which are recognizable by a computer 20, a speed sensor 1 installed on wheels of the train to generate a pulse signal corresponding to the rate of rotation of the wheels during travel; a frequency/voltage converter 2 for converting the frequency of an discontinuous pulse detected through the speed sensor 1 into a voltage; a first A/D converter 3 for converting an analog train speed voltage output from the frequency/voltage converter 2 into a digital signal; a train speed detector 4 for receiving the output signal of the first A/D converter 3 input thereto and detecting the current travel speed of the train; a counter 5 for counting the discontinuous pulse detected through the speed sensor 1; a position information detector 6 for receiving an output signal of the counter 5 and detecting the position of the train by calculating the travel distance of the train corresponding to the number of pulses; a block force measurement sensor installed in a brake of the train to detect a block force; a braking force measurement sensor installed in the brake of the train to detect braking force; a strain amplifier 18 for amplifying detection signals of block force and braking force detected through the block force and braking force measurement sensor 14; a second A/D converter 19 for converting the analog signals of block force and braking force output through the strain amplifier 18 into digital signals; and the computer 20 for receiving and memorizing output signals from the aforementioned elements in real time and for, when a fault occurs in a specific brake, memorizing and outputting the travel speed, position, state information about various relays, and fault status information about the brake given at that time.
In addition, the conventional fault diagnosis system for a train brake configured as above measures block force (braking pressure) and braking force, MASCON powering, braking state information, VCB state, dead section entrance/pass status, a travel speed and position information during travel and recognizes braking force according to change in the train to determine a fault status.
Although the conventional fault diagnosis system presents a fault diagnosis method for a brake of a train, this method is not based on a dynamic model. Thereby, the conventional fault diagnosis system causes the driver to measure not only MASCON input information but also the braking pressure and braking force.
In addition, in a wireless communication-based train control system, a speed limit for travel of a train is presented by an automatic train protection (ATP), which is an automatic system for protection of the train. If the travel speed of the train exceeds the speed limit, the ATP functions to stably stop the train by outputting an emergency braking command in order to protect the train. When the train is automatically operated in the automatic mode or unmanned mode, the automatic train operation (ATO) system substituting the engineer configures a travel speed profile based on the train speed limit received from the ATP, and accelerates or decelerates the train by transferring powering output to a powering device of the train or transferring common braking output to the brake of the train. For the common braking output, a common braking command is output is output to the brake if the current speed of the train exceeds a speed in the configured speed profile. Upon receiving the signal, the brake controls the train to decelerate by generating braking force in the brake system. However, if the brake of the train or an interface between the ATO and the brake malfunctions and thus braking performance is degraded, desired braking force is not generated in the train, and thus the speed of the train may exceed a speed in the configured speed profile. Thereby, an emergency braking command may be output from the ATP, and the train may stop on the way to a station. Application of emergency braking to the train in the automatic mode or unmanned mode is managed by the ATP to ensure a safe travel of the train. If the speed of the train exceeds the speed limit for safety, an emergency braking command is output to the train to decelerate the train, and the emergency braking state is maintained until the train stops. Once the train stops, emergency braking is released. Once the train is stopped by emergency braking on the way to a station, the train may be automatically restarted by a restart command from the control center after the emergency braking output is mitigated, but performance may still be degraded because the cause of performance degradation of the brake of the train has not been eliminated. In addition, when the train is restarted and the speed of the train exceeds a speed in the configured speed profile, emergency braking may be applied by the ATP. In this case, the train will be stopped again on the way to a station, and this operation will be repeated until the train arrives at the next station. In another case, the engineer may need ride on the train stopped on the way to the next station and to manually move the train to the next station.
Since the train can avoid collision with a following train only when the fault diagnosis of the brake of the train is performed and the train having a malfunctioning brake is moved to a safe position, the train may be considered as finally having escaped from a danger of an accident. However, the conventional fault diagnosis apparatus for a brake of a train performs only diagnosis of faults of the brake of the train, and fails to present a technology for moving the train to a safe position when the brake malfunctions. Accordingly, the conventional fault diagnosis apparatus cannot perfectly protect the train from an accident when the brake malfunctions.